/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the demonstration applications of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/

#ifndef VELOCITYTRACKER_H
#define VELOCITYTRACKER_H

#include <QBasicTimer>
#include <QObject>

class QMouseEvent;
class QPoint;
class VelocityTrackerPrivate;

class VelocityTracker : public QObject
{
    Q_OBJECT
public:

    VelocityTracker(QObject *parent);
    ~VelocityTracker();

    bool isScrolling() const;
    void stopAutoScrolling();

    void setThreshold(int threshold);
    int  threshold() const;

    void setTickInterval(int interval);

    void handleMousePress(QMouseEvent *event);
    void handleMouseMove(QMouseEvent *event);
    void handleMouseRelease(QMouseEvent *event);

signals:
    void changedDelta(const QPoint &delta);

private:
    void start(int interval) {
        if (!m_timer.isActive())
            m_timer.start(interval, this);
    }

    void stop() {
        m_timer.stop();
    }

protected:
    void timerEvent(QTimerEvent *event) {
        Q_UNUSED(event);
        tick();
    }

private:
    void tick();

private:
    VelocityTrackerPrivate *d;
    QBasicTimer m_timer;
};

#endif // VELOCITYTRACKER_H
